Comparison of Passive Microwave Data with Shipborne Photographic Observations of Summer Sea Ice Concentration along an Arctic Cruise Path

Arctic sea ice concentration (SIC) has been studied extensively using passive microwave (PM) remote sensing. This technology could be used to improve navigation along vessel cruise paths; however, investigations on this topic have been limited. In this study, shipborne photographic observation (P-OBS) of sea ice was conducted using oblique-oriented cameras during the Chinese National Arctic Research Expedition in the summer of 2016. SIC and the areal fractions of open water, melt ponds, and sea ice (Aw, Ap, and Ai, respectively) were determined along the cruise path. The distribution of SIC along the cruise path was U-shaped, and open water accounted for a large proportion of the path. The SIC derived from the commonly used PM algorithms was compared with the moving average (MA) P-OBS SIC, including Bootstrap and NASA Team (NT) algorithms based on Special Sensor Microwave Imager/Sounder (SSMIS) data; and ARTIST sea ice, Bootstrap, Sea Ice Climate Change Initiative, and NASA Team 2 (NT2) algorithms based on Advanced Microwave Scanning Radiometer 2 (AMSR2) data. P-OBS performed better than PM remote sensing at detecting low SIC (< 10%). Our results indicate that PM SIC overestimates MA P-OBS SIC at low SIC, but underestimates it when SIC exceeds a turnover point (TP). The presence of melt ponds affected the accuracy of the PM SIC; the PM SIC shifted from an overestimate to an underestimate with increasing Ap, compared with MA P-OBS SIC below the TP, while the underestimation increased above the TP. The PM algorithms were then ranked; SSMIS-NT and AMSR2-NT2 are the best and worst choices for Arctic navigation, respectively

Effect of short-term aging on rheological properties of bio-asphalt/SBS/PPA composite modified asphalt

Substituting petroleum asphalt with bio-asphalt produced by biological waste recycling can mitigate the dependence on non-renewable resource oil. This study aimed to investigate the effectiveness of bio-asphalt as a substitute for petroleum asphalt by analyzing its rheological properties. Therefore, in this study, modified asphalt was prepared using styrene-butadiene-styrene copolymer (SBS), polyphosphoric acid (PPA), and bio-asphalt (BA) as modifiers, and the short-term aging test of the modified asphalt was carried out. Then the rheological properties of the modified asphalt were analyzed through the Temperature Scanning (TS) test, the Multiple Stress Creep Recovery (MSCR) test, and the Bending Beam Rheometer (BBR) test; finally, the Fourier Transform infrared spectroscopy (FTIR) test, Fluorescence Microscopy (FM) test to study the modification mechanism and microscopic characteristics of asphalt. The results show that adding BA improved the low-temperature rheological properties of modified asphalt while reducing the high-temperature rheological properties of PPA modified asphalt. The BA, SBS, and PPA combination exhibited excellent performance in high and low-temperature conditions. The short-term aging process enhances the high-temperature rutting resistance of modified asphalt but adversely affects its low-temperature performance. Fluorescence microscopy tests have demonstrated that BA improves the compatibility of SBS and PPA in asphalt. Meanwhile, FTIR has revealed that BA and SBS are physically mixed, and BA and PPA undergo a chemical reaction. This study suggests that BA could be a viable and sustainable alternative to petroleum asphalt, with promising performance characteristics when combined with SBS and PPA modifiers

Raman spectroscopy analysis of the biochemical characteristics of molecules associated with the malignant transformation of gastric mucosa.

OBJECTIVE: The purpose of this study was to comparatively analyze the signature Raman spectra of genomic DNA, nuclei, and tissue of normal gastric mucosa and gastric cancer and to investigate the biochemical transformation of molecules associated with gastric mucosa malignancy. METHOD: Genomic DNA, nuclei, and tissue from normal gastric mucosa and gastric cancer were analyzed by Raman spectroscopy. RESULTS: 1) The Raman spectrum of gastric cancer genomic DNA showed that two peaks appeared, one at approximately 1090 cm-1 with a higher intensity than the peak at 1050 cm-1 in the spectrum. Characteristic peaks appeared at 950 cm-1, 1010 cm-1, and 1100-1600 cm-1. 2) Using a hematoxylin and eosin (H&E)-stained section, the intensity of the characteristic peak of nucleic acids at 1085 cm-1 was increased and shifted to 1088 cm-1 in cancer cells. The relative intensity of the characteristic peaks of nucleoproteins at 755 cm-1 and 1607 cm-1 was significantly increased in cancer cells compared with normal cells. 3) Compared with normal tissues, the peak representing PO2- symmetric stretching vibration shifted from 1088 cm-1 to 1083 cm-1 in cancer tissue, and the characteristic peak for collagen at 938 cm-1 shifted to 944 cm-1. In addition, an extra characteristic peak indicating C = C stretching vibration appeared at 1379 cm-1 in the lipid spectrum in cancer tissue. CONCLUSIONS: The position, intensity, and shape of peaks in the Raman spectra of DNA, nuclei, and tissue from gastric cancer were significantly different compared with those of normal cells. These results indicate that the DNA phosphate backbone becomes unstable in cancer cells and might be broken; the relative content of histones is increased and stable; the relative collagen content is reduced, facilitating cancer cell metastasis; and the relative content of unsaturated fatty acids is increased, increasing the mobility of the plasma membrane of cancer cells

A point interpolation method with locally smoothed strain field (PIM-LS2) for mechanics problems using triangular mesh

A point interpolation method with locally smoothed strain field (PIM-LS2) is developed for mechanics problems using a triangular background mesh. In the PIM-LS2, the strain within each sub-cell of a nodal domain is assumed to be the average strain over the adjacent sub-cells of the neighboring element sharing the same field node. We prove theoretically that the energy norm of the smoothed strain field in PIM-LS2 is equivalent to that of the compatible strain field, and then prove that the solution of the PIM- LS2 converges to the exact solution of the original strong form. Furthermore, the softening effects of PIM-LS2 to system and the effects of the number of sub-cells that participated in the smoothing operation on the convergence of PIM-LS2 are investigated. Intensive numerical studies verify the convergence, softening effects and bound properties of the PIM-LS2, and show that the very ‘‘tight’’ lower and upper bound solutions can be obtained using PIM-LS2

Identification of Lesional Tissues and Nonlesional Tissues in Early Gastric Cancer Endoscopic Submucosal Dissection Specimens Using a Fiber Optic Raman System

Aim. To identify lesional and nonlesional tissues from early gastric cancer (EGC) patients by Raman spectroscopy to build a diagnostic model and effectively diagnose EGC. Method. Specimens were collected by endoscopic submucosal dissection from 13 patients with EGC, and 55 sets of standard Raman spectral data (each integrated 10 times) were obtained using the fiber optic Raman system; there were 33 sets of lesional tissue data, including 18 sets of high-grade intraepithelial neoplasia (HGIN) data and 15 sets of adenocarcinoma data, and 22 sets of nonlesional tissue data. After the preprocessing steps, the average Raman spectrum was obtained. Results. The nonlesional tissues showed peaks at 891 cm-1, 1103 cm-1, 1417 cm-1, 1206 cm-1, 1234 cm-1, 1479 cm-1, 1560 cm-1, and 1678 cm-1. Compared with the peaks corresponding to nonlesional tissues, the peaks of the lesional tissues shifted by different magnitudes, and a new characteristic peak at 1324 cm-1 was observed. Comparing the peak intensity ratio and the integral energy ratio of the lesional tissues with those of the nonlesional tissues revealed a significant difference between the two groups (independent-samplest-test, P<0.05). Considering the peak intensity ratio of I1560 cm-1/I1103 cm-1 as a diagnostic indicator, the accuracy, sensitivity, and specificity of diagnosing EGC were 98.8%, 93.9%, and 91.9%, respectively. Considering the integral energy ratio (noncontinuous frequency band and continuous frequency band) as a diagnostic indicator, the accuracy, sensitivity, and specificity of diagnosing EGC were 99.2-99.6%, 93.9-97.0%, and 95.5%, respectively. Conclusions. The integral energy ratio of the Raman spectrum could be considered an effective indicator for the diagnosis of EGC

Raman spectra of 15 gastric cancer tissues.

<p>Raman spectra of 15 gastric cancer tissues.</p

Ratio of relative peak intensity (Two Independent Sample t-Test).

<p>Ratio of relative peak intensity (Two Independent Sample t-Test).</p

Tentative assignments of Raman bands (human tissue).

<p><i>ν</i>: stretching vibration, <i>νa</i>s: asymmetric stretching vibration, <i>ν</i>s: symmetric stretching vibration, δ: bending, deformed, swing (relative peak intensity = the peak intensity/average intensity of the full spectrum).</p